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Control Systems Questions and Answers – Time Response of First Order Systems

This set of Control Systems Multiple Choice Questions & Answers (MCQs) focuses on “Time Response of First Order Systems”.

1. First order system is defined as :
a) Number of poles at origin
b) Order of the differential equation
c) Total number of poles of equation
d) Total number of poles and order of equationView Answer

Answer: d
Explanation: First order system is defined by total number of poles and also which is same as the order of differential equation.

2. A unit step is applied at t=0 to a first order system without time delay. The response has the value of 1.264 units at t=10 mins, and 2 units at steady state. The transfer function of the system is_____________
a) 3/(1+600s)
b) 2/(1+500s)
c) 5/(1+220s)
d) 2/(1+600s)View Answer

3. The transfer function of the system is G(s) =100/(s+1) (s+100). For a unit step input to the system the approximate settling time for 2% criterion is:
a) 100 sec
b) 4 sec
c) 1 sec
d) 0.01 secView Answer

Answer: b
Explanation: G(s) =100/(s+1) (s+100)
Taking the dominant pole consideration,
S=-100 pole is not taken.
G(s)= 100/s+1
Now it is first order system, ts=4T=4 sec.

4. If a first order system and its time response to a unit step are as shown below, the gain K is :

8. Assertion (A): It is observed that step function is first derivative of a ramp function and impulse function is first derivative of a step function.
Reason (R): From the derived time response expression it is concluded that the output time response also follows the same sequence as that of input functions.
a) Both A and R are true and R is the correct explanation of A
b) Both A and R are true but R is not correct explanation of A
c) Both A is True but R is false
d) Both A is False but R is trueView Answer

Answer: b
Explanation: If response due to one standard signal is known then response due to other signals can also be derived.